U.S. patent number 6,986,754 [Application Number 10/101,400] was granted by the patent office on 2006-01-17 for needleless hypodermic injection system, application device and medication cartridge therefor.
This patent grant is currently assigned to Roche Diagnostics GmbH. Invention is credited to Dirk Bandau, Otto Bruntrup, Horst Engelhardt, Christian Gliewe, Hans-Peter Haar, Guenter Franz Ihle, Hans List, George Bevan Kirby Meacham, Konrad Joseph Popp, Ulrich Josef Riemensperger, Bruno Robert Thos.
United States Patent |
6,986,754 |
Haar , et al. |
January 17, 2006 |
**Please see images for:
( Certificate of Correction ) ** |
Needleless hypodermic injection system, application device and
medication cartridge therefor
Abstract
A needleless hypodermic injection system for injecting a liquid
medication, which system comprises a disposable cartridge which
contains a medication and which includes a propellant and an
igniter, and a reusable application device which comprises a
pressure chamber for receiving the medication cartridge, actuation
means including an ignition system and means for ensuring
reliability and safety of the system. The reusable application
device comprises: (a) a housing including a fist housing section
and a second housing section which are adapted to be assembled
together by a screwing operation, the first housing section
comprising a front part having an injection outlet and a chamber
adapted to receive a the cartridge contains the medication to be
injected and also contains a propellant and an igniter, and (b)
means for selectively activating said igniter of said cartridge
when predetermined conditions are fulfilled.
Inventors: |
Haar; Hans-Peter (Wiesloch,
DE), Meacham; George Bevan Kirby (Shaker Heights,
OH), Popp; Konrad Joseph (Augsburg, DE), Bruntrup;
Otto (Munich, DE), Riemensperger; Ulrich Josef
(Edenried-Aichach, DE), Ihle; Guenter Franz (Mauer,
DE), Thos; Bruno Robert (Quierschied, DE),
List; Hans (Hesseneck, DE), Bandau; Dirk
(Ottersheim, DE), Engelhardt; Horst (Neuhofen,
DE), Gliewe; Christian (Lampertheim, DE) |
Assignee: |
Roche Diagnostics GmbH
(Mannheim, DE)
|
Family
ID: |
23063444 |
Appl.
No.: |
10/101,400 |
Filed: |
March 19, 2002 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20020169412 A1 |
Nov 14, 2002 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
60278042 |
Mar 22, 2001 |
|
|
|
|
Current U.S.
Class: |
604/70 |
Current CPC
Class: |
A61M
5/30 (20130101); A61M 5/5086 (20130101); A61M
2005/2013 (20130101); A61M 2005/3118 (20130101); A61M
5/2046 (20130101); A61M 5/3129 (20130101); A61M
2205/582 (20130101); A61M 2205/583 (20130101); A61M
5/2425 (20130101); A61M 2005/312 (20130101) |
Current International
Class: |
A61M
5/30 (20060101) |
Field of
Search: |
;604/68-72,131,140,143 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1 013 297 |
|
Jun 2000 |
|
EP |
|
2 796 291 |
|
Jan 2001 |
|
FR |
|
WO 98 13085 |
|
Apr 1998 |
|
WO |
|
WO 98/31409 |
|
Jul 1998 |
|
WO |
|
WO 01 05451 |
|
Jan 2001 |
|
WO |
|
Primary Examiner: Kennedy; Sharon
Attorney, Agent or Firm: Johnston; George W.
Rocha-Tramaloni; Patricia S. Prior; Kimberly J.
Claims
What is claimed is:
1. A reusable application device for a needleless hypodermic
injection system for injecting a liquid medication, which
application device comprises: (a) a housing including a first
housing section and a second housing section which are adapted to
be assembled together by a screwing operation, said first housing
section comprising a front part having an injection outlet and a
chamber adapted to receive a cartridge containing a medication unit
which contains the medication to be injected, a propellant, and an
igniter, (b) means for selectively activating said igniter of said
cartridge when predetermined conditions are fulfilled, and (c)
means providing a visual or audible indication to the user when
said predetermined conditions are met and the device is ready for
performing an injection.
2. A reusable application device for a needleless hypodermic
injection system for injecting a liquid medication contained in a
cartridge inserted into said application device, said application
device comprising: a) a housing including a first section and a
second section which are adapted to be connected with each other to
form a housing assembly, said first housing section comprising a
chamber for receiving a cartridge containing a medication unit
which contains a liquid medication, said first housing section
having a symmetry axis which extends along its length and a front
part having an outer contact surface which is adapted to be applied
on a skin surface, said contact surface having an opening through
which liquid medication ejected from said cartridge can pats and be
injected through said skin surface, b) ejection means for causing
ejection of said liquid medication contained in said cartridge in
order to perform an injection, a first part of said ejection means
being contained in said cartridge and a second part of said
ejection means being contained in said second housing section, c)
assembly detecting means which reach a first predetermined state
when said first housing section is properly and completely
assembled with said second housing section to form said housing
assembly, said assembly detecting means being located within said
housing assembly, d) position detecting means which are located in
part within said first housing section and in part in said second
housing section, said position detecting means reaching a second
predetermined state when the following conditions are
simultaneously satisfied by the relative position of said housing
assembly with respect to said skin surface, d.2) said contact
surface of said first section exerts a predetermined pressure on
said skin surface, the distribution of said pressure over the area
of said contact surface being substantially uniform, and d.3) said
symmetry axis of said first section is positioned substantially
normal to said skin surface, and e) actuator means for activating
said election means, said actuator means being normally disabled
and becoming operable only upon being enabled by a combination of
predetermined effects provided by said assembly detecting means
after they reach said first predetermined state, and said position
detecting means when they reach said second predetermined
state.
3. A device according to claim 2, wherein said second housing
section comprises means which are adapted to cooperate with a
corresponding part of said first housing section for clamping with
a predetermined preload and for hermetically closing a cartridge
inserted into said cartridge receiving chamber.
4. A device according to claim 2, wherein said assembly detecting
means exclusively comprise mechanical means.
5. A device according to claim 2, wherein said position detecting
means exclusively comprise mechanical and electro-mechanical means,
but no electronic means sensitive to electrical noise or other
perturbating electrical signals.
6. A device according to claim 2, wherein said position detecting
means comprise a first switch adapted to be mechanically actuated
by a movable part of said position detecting means to establish an
electrical connection when said position detecting means senses
application of said front part of said first housing part on said
skin surface with a predetermined pressure applied on the skin
surface.
7. A device according to claim 2, wherein said first housing part
and said second housing part are so shaped, dimensioned and
configured that proper and complete assembly thereof is accurately
defined and recognizable by visual and tactile inspection.
8. A device according to claim 2, wherein said first housing part
and said second housing part are adapted to be assembled together
by assembling steps which include a screwing operation.
9. A reusable application device according to claim 2, wherein said
housing assembly is so configured and dimensioned that it is
adapted to be held and used by a user with only one hand.
10. A reusable application device according to claim 2, which
further comprises means providing a visual or audible indication to
the user when said actuator device is enabled by said combination
of predetermined effects.
11. A reusable application device for a needleless hypodermic
injection system for injecting a liquid medication contained in a
cartridge inserted into said application device, said cartridge
containing a propellant adapted to be ignited by application of
electrical energy to two electrical contacts which are part of said
cartridge, said application device comprising: a) a housing
including a first section and a second section, each of these
sections having a length axis and said first and second housing
sections being adapted to be connected with each other to form a
housing assembly, said housing assembly being so configured and
dimensioned that it is adapted to be held by a user with one hand,
b) said first housing section comprising a chamber for receiving a
cartridge containing a liquid medication, said first section having
an outer contact surface which is adapted to be applied on a skin
surface through which an injection is to be applied, c) said second
housing section containing electrical means for causing ignition of
a propellant contained in a cartridge arranged in said chamber of
said first housing section and actuator means for activating said
electrical means, and d) position detecting means for detecting
whether said contact surface of said first section exerts a
predetermined pressure on said skin surface and whether at the same
time said length axis of said first section is positioned
substantially normal to said skin surface, the distribution of said
pressure over the area of said contact surface being substantially
uniform, said means for detecting enabling said actuator means when
the latter conditions are satisfied.
12. A device according to claim 11, wherein said second housing
section comprises means which are adapted to cooperate with a
corresponding part of said first housing section for clamping with
a predetermined preload and for hermetically closing a cartridge
inserted into said cartridge receiving chamber.
13. A reusable application device for a needleless hypodermic
injection system for injecting a liquid medication, which
application device comprises: (a) a housing including a first
housing section and a second housing section which are adapted to
be assembled together by a screwing operation, said first housing
section comprising a front part having an injection outlet and a
chamber adapted to receive a cartridge containing a medication unit
which contains the medication to be injected, a propellant, and an
igniter, and (b) means for selectively activating said igniter of
said cartridge when predetermined conditions are fulfilled, wherein
said means for selectively activating said igniter comprise a
purely mechanical object sensor, and a first switch adapted to be
mechanically actuated by a movable part of said object sensor to
establish an electrical connection when said object sensor senses
application of said front part of said first housing part on a body
part.
14. A reusable application device for a needleless hypodermic
injection system for injecting a liquid medication, which
application device comprises: (a) a housing including a first
housing section and a second housing section which are adapted to
be assembled together by a screwing operation, said first housing
section comprising a front part having an injection outlet and a
chamber adapted to receive a cartridge containing a medication unit
which contains the medication to be injected, a propellant, and an
igniter, and (b) means for selectively activating said igniter of
said cartridge when predetermined conditions are fulfilled, wherein
at least part of said means for selectively activating said igniter
are lodged within said second housing part and comprise an
electrical circuit including a battery, said first switch a second
switch adapted to be actuated by a user, interconnection
conductors, and two electrical terminals which correspond to
respective terminals of said igniter, said electrical circuit being
so configured that electrical current can flow from the battery to
the igniter only when the following conditions are met: i) said
cartridge is properly positioned within said chamber of said first
housing part, ii) said first and said second housing part are
completely and properly assembled, whereby said two terminals of
said electrical circuit contact said respective terminals of said
igniter, iii) said first switch is actuated by said object sensor
and thereby establishes an electrical connection, and iv) said
second switch is actuated by a user.
15. A medication cartridge for a needleless hypodermic injection
system for injecting a liquid medication, said cartridge comprising
a housing adapted to contain: (a) a first chamber containing a
medication unit configured and dimensioned to store a volume of
liquid to be injected, said medication unit having a first region
and a second region that are in liquid communication with each
other, said first region being deformable and said second region
having an injection outlet, and (b) a second chamber containing a
propellant, said first chamber being divided by an elastic baffier
in two zones, a first zone containing said medication unit and a
second zone which is communication with said second chamber, so
that upon ignition of the propellant in the second chamber gas
generated thereby expands into said second zone of said first
chamber, exerts pressure on and deforms said baffier which in turn
transfers that pressure to and deforms said deformable first region
of said medication unit and thereby causes ejection of said
medication through said injection outlet, and (c) means for
mechanically setting the volume available within said cartridge for
gas said expansion, so that said volume has a selected
predetermined size.
16. A medication cartridge according to claim 15, which further
comprises an envelope which surrounds said elastic barrier and
protects it from direct contact with hot gas generated by ignition
of said propellant in said second chamber.
17. A medication cartridge according to claim 16, wherein said
envelope also forms a gas seal between said housing and said
medication unit containing said liquid medication.
Description
FIELD OF THE INVENTION
The invention concerns a needleless hypodermic injection system for
injecting a liquid medication.
The invention also concerns a reusable application device which is
a first part of such a system.
The invention further concerns a disposable medication cartridge
which is a second part of such a system.
BACKGROUND OF THE INVENTION
Prior art systems and devices of the above mentioned kind have
important disadvantages. They have a complex structure and are
therefore not easy to assemble and to use, in particular for
patients which have some handicaps or are not in full possession of
their handling capabilities. Moreover they lack reliable means for
preventing accidental release of injections and their negative
consequences, e.g. loss of expensive medications and possible
injures inflicted to the user.
The main aim of the instant invention is therefore to provide a
system an application device, and a medication cartridge of the
above mentioned kind with which the above mentioned drawbacks can
be eliminated or at least substantially reduced.
SUMMARY OF THE INVENTION
According to a first aspect of the invention the above mentioned
aim is attained with a needleless hypodermic injection system for
injecting a liquid medication, which system comprises: (a) a
disposable cartridge which contains a medication and which includes
a propellant and an igniter, and (b) a reusable application device
which comprises a pressure chamber for receiving said cartridge,
and actuation means including an ignition system and means for
ensuring reliability and safety of the system.
According to a second aspect of the invention the above mentioned
aim is attained with a reusable application device for a needleless
hypodermic injection system for injecting a liquid medication
contained in a cartridge inserted into said application device,
said application device comprising (a) a housing including a first
section and a second section which are adapted to be connected with
each other to form a housing assembly, said first housing section
comprising a chamber for receiving a cartridge containing a
medication unit which contains a liquid medication, said first
housing section having a symmetry axis which extends along its
length and a front part having an outer contact surface which is
adapted to be applied on a skin surface, said contact surface
having an opening through which liquid medication ejected from said
cartridge can pass and be injected through said skin surface, (b)
ejection means for causing ejection of said liquid medication
contained in said cartridge in order to perform an injection, a
first part of said ejection means being contained in said cartridge
and a second part of said ejection means being contained in said
second housing section, c) assembly detecting means which reach a
first predetermined state when said first housing section is
properly and completely assembled with said second housing section
to form said housing assembly, said assembly detecting means being
located within said housing assembly, d) position detecting means
which are located in part within said first housing section and in
part in said second housing section, said position detecting means
reaching a second predetermined state when the following conditions
are simultaneously satisfied by the relative position of said
housing assembly with respect to said skin surface, d.2) said
contact surface of said first section exerts a predetermined
pressure on said skin surface, the distribution of said pressure
over the area of said contact surface being substantially uniform,
and d.3) said symmetry axis of said first section is positioned
substantially normal to said skin surface, and e) actuator means
for activating said ejection means, said actuator means being
normally disabled and becoming operable only upon being enabled by
a combination of predetermined effects provided by said assembly
detecting means after they reach said first predetermined state,
and said position detecting means when they reach said second
predetermined state.
According to a third aspect of the invention the above mentioned
aim is attained with a reusable application device for a needleless
hypodermic injection system for injecting a liquid medication
contained in a cartridge inserted into said application device,
said cartridge containing a propellant adapted to be ignited by
application of electrical energy to two electrical contacts which
are part of said cartridge, said application device comprising a) a
housing including a first section and a second section, each of
these sections having a length axis and said first and second
housing sections being adapted to be connected with each other to
form a housing assembly, said housing assembly being so configured
and dimensioned that it is adapted to be held by a user with one
hand, b) said first housing section comprising a chamber for
receiving a cartridge containing a liquid medication, said first
section having an outer contact surface which is adapted to be
applied on a skin surface through which an injection is to be
applied, c) said second housing section containing electrical means
for causing ignition of a propellant contained in a cartridge
arranged in said chamber of said first housing section and actuator
means for activating said electrical means, and d) position
detecting means for detecting whether said contact surface of said
first section exerts a predetermined pressure on said skin surface
and whether at the same time said length axis of said first section
is positioned substantially normal to said skin surface, the
distribution of said pressure over the area of said contact surface
being substantially uniform, said means for detecting enabling said
actuator means when the latter conditions are satisfied.
According to a fourth aspect of the invention the above mentioned
aim is attained with a reusable application device for a needleless
hypodermic injection system for injecting a liquid medication,
which application device comprises: (a) a housing including a fist
housing section and a second housing section which are adapted to
be assembled together by a screwing operation, said first housing
section comprising a front part having an injection outlet and a
chamber adapted to receive a cartridge containing a medication unit
which contains the medication to be injected, a propellant, and an
igniter, and (b) means for selectively activating said igniter of
said cartridge when predetermined conditions are fulfilled.
According to a fifth aspect of the invention the above mentioned
aim is attained with a medication cartridge for a needleless
hypodermic injection system for injecting a liquid medication, said
cartridge comprising a housing adapted to contain: (a) a first
chamber containing a medication unit configured and dimensioned to
store a volume of liquid to be injected, said medication unit
having a first region and a second region that are in liquid
communication with each other, said first region being deformable
and said second region having an injection outlet, and (b) a second
chamber containing a propellant, said first chamber being divided
by an elastic barrier in two zones, a first zone containing said
medication unit and a second zone which is communication with said
second chamber, so that upon ignition of the propellant in the
second chamber gas generated thereby expands into said second zone
of said first chamber, exerts pressure on and deforms said barrier
which in turn transfers that pressure to and deforms said
deformable first region of said medication unit and thereby causes
ejection of said medication through said injection outlet, and (c)
means for mechanically setting the volume available within said
cartridge for gas said expansion, so that said volume has a
selected predetermined size.
The main advantages attained with the invention are as follows:
Injections can only be performed when plurality of predetermined
necessary conditions for a correct injection are satisfied.
Therefore, the risk of accidentally released injections and their
negative consequences, e.g. loss of expensive medications and
possible injure of user, are substantially reduced. A device and a
system according to the invention are easy, safe and comfortable to
use, so that they can be assembled and used by patients or other
persons without any training or special instructions. The
manufacturing cost of a device and a system according to the
invention is not higher than prior art devices for the same
purpose.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject invention will now be described in terms of its
preferred embodiments with reference to the accompanying drawings.
These embodiments are set forth to aid the understanding of the
invention, but are not to be construed as limiting.
FIG. 1 shows a schematic cross sectional view of a basic structure
of a medication cartridge 11 used in a needleless injection system
according to the invention.
FIG. 2 shows a schematic cross sectional view of the basic
structure of an application device according to the invention
including a representation of a medication cartridge 11 according
to FIG. 1.
FIG. 3 shows a schematic cross sectional view of the pressure
chamber and locking means which are part of the application device
according to FIG. 2 and which are adapted to enclose and contain a
medication cartridge 11 of the type shown by FIG. 1 during a
high-pressure injection.
FIG. 4 shows a schematic cross sectional view of a complete
application device according to the invention without a medication
cartridge inserted thereinto.
FIG. 5 shows a side view of the nose section 42 of an application
device of the kind shown by FIG. 4.
FIG. 6 shows a first perspective view of the nose section 42 shown
by FIG. 5.
FIG. 7 shows a second perspective view of the nose section 42 shown
by FIG. 5.
FIG. 8 shows a first exploded view of components of the nose
section 42 shown by FIGS. 5-7.
FIG. 9 shows a second exploded view of components of the nose
section 42 shown by FIGS. 5-7.
FIG. 10 shows a first schematic representation of the electrical
ignition circuit of an application device of the kind shown by FIG.
4.
FIG. 11 shows a second schematic representation of the electrical
ignition circuit of an application device of the kind shown by FIG.
4.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
According to the invention a reusable application device is used as
part of a needleless hypodermic injection system for injecting a
liquid medication contained in a cartridge inserted into said
application device.
Medication Cartridge Assembly
As shown by FIG. 1 a medication cartridge assembly 11 according to
the invention comprises components described hereinafter.
A cartridge shell 12 made e.g. of a plastic material contains among
other components a sealed medication module which comprises a
nozzle body 13 and a flexible container wall 14 that hermetically
encloses a portion of the nozzle and forms a reservoir 15 for a
liquid medication 16 stored in the sealed medication module. This
sealed module including liquid medication 16 stored therein is
manufactured under sterile conditions.
A part of the container wall 14 forms a break-off protective cap 17
that covers a jet orifice 18 of nozzle body 13. Cap 17 is removed
by the user just prior to use.
An envelope 21 made e.g. of rubber surrounds the flexible container
wall 14 and serves as a protective barrier. Envelope 21 protects
flexible wall 14 from direct hot gas contact, and prevents hot gas
from entering a fluid channel 22 within nozzle body 13 and jet
orifice 18 of nozzle body 13 even in the event of a break in the
flexible container wall 14. Envelope 21 also forms a gas seal
between the cartridge shell 12 and the medication module containing
the liquid medication 16.
Cartridge shell 12 unifies the components contained therein and
contains also gas generated within cartridge shell 12 by a gas
generator contained therein during actuation. The wall of cartridge
shell 12 may be relatively thin since it transfers the gas pressure
forces generated within cartridge shell 12 to a surrounding high
strength chamber that is part of a reusable actuation device
described hereinafter.
Injection energy is provided by a gas generator located in the rear
part of cartridge shell 12. This gas generator is a subassembly
consisting of a metal gas generator body 23 which has a propellant
containing chamber 24 located between an outlet orifice plate 25
and a closure plug or closure plate 26. When the gas generator is
actuated in order to provide the energy necessary for performing an
injection of the liquid medication, a propellant contained in
propellant chamber 24 is ignited by an electrically heated wire and
produces hot gas that flows to gas pressure chamber 27 surrounding
envelope 21, flexible container wall 14 and medication reservoir 15
and an annular co-volume 28 the size of which is defined by the
axial position of a co-volume seal ring 34.
Heating wire adapted to be electrically heated is arranged within
propellant chamber 24. This heating wire is electrically connected
with ignition contacts 31, 32 arranged in closure plate. When the
medication cartridge assembly is properly positioned within the
reusable application device ignition contacts 31, 32 engage
corresponding electrical contacts which are part of the application
device described hereinafter. Electric power is deliverable to the
heating wire 35 (shown in FIG. 11) arranged within propellant
chamber 24 through the latter contacts and ignition contacts 31, 32
engaged therewith.
Cartridge shell 12 further contains an internal support 33 which
e.g. a structure made of a plastic material that snaps into
cartridge shell 12 and holds the above described sealed medication
module and the gas generator in position. When cartridge assembly
11 is inserted into and properly positioned within an application
device described hereinafter in order to perform an injection, a
part of this application device pushes on the rear of cartridge
assembly 11 and clamps the closure plate 26 of the gas generator,
internal support 33, envelope 21 and the above described sealed
medication module into the nose of cartridge shell 12. Cartridge
assembly 11 remains so clamped during actuation thereof by the
application device for performing the injection. This clamping
action on cartridge assembly 11 assures that this assembly is
hermetically sealed to prevent hot gas leakage around jet orifice
18 of nozzle body 13.
When a cartridge assembly is actuated by the application device,
pressure exerted by gas surrounding a part of the sealed medication
module within cartridge shell 12 is transmitted to liquid
medication 16 contained in the sealed medication module through
flexible container wall 14. The pressure exerted in this way on the
liquid medication causes a collapsing of flexible container wall 14
and this drives the liquid medication through jet orifice 18 at
high velocity. Peak pressure, up to 300 bar, occurs at the
beginning of the injection and forces a jet of liquid medication to
penetrate through a skin layer and thereby form a fluid delivery
channel into the subcutaneous tissue. The pressure then drops to
about 100 bar to complete the medication injection through the so
formed fluid delivery channel.
Ease of jet penetration varies between patients or between
injection sites on the same patient. The initial peak injection
pressure is therefore adjusted to control the jet penetration force
to an appropriate value. This adjustment is effected by positioning
co-volume seal ring 34 at a suitable axial position with respect to
cartridge shell 12 in order to set the value of the annular
co-volume 28.
Increasing co-volume 28 increases the expansion volume of the gas
generated and delivered by the gas generator and reduces the
initial peak pressure to a lower value. A co-volume setting ring 48
that is part of the application device described hereinafter slides
into the rear of cartridge 11 during loading of cartridge 11 into
the application device, brings co-volume seal ring 34 into a
selected position and holds this ring in this position.
A cartridge assembly 11 clamped into the actuation device described
hereinafter is a hermetically sealed assembly, and retains as much
as 100 bars pressure after actuation. The application device must
therefore release the clamping force in a controlled way and allow
that the gas pressure within cartridge 11 forces closure plug 26 of
the gas generator out to break the seal with the gas generator body
23 and vent the gas. This controlled pressure release makes it easy
to open the application device after it is used to perform an
injection and prevents that the amount of pressure remaining in the
cartridge after an injection may cause an undesirable forceful
opening of the application device that may cause an injury to a
user of the device.
Structure of an Application Device According to the Invention
The above described characteristics of cartridge assembly 11 define
the basic functional requirements the application device has to
satisfy. Additional requirements ensure safe and easy operation of
the application device.
The force a user has to apply for loading a cartridge 11 into an
application device and the force a user has to apply for removing a
cartridge 11 from the application device after use for performing
an injection must be low enough to allow easy and sure operation of
the application device by ill or elderly patients.
Actuation of the application device must not be possible unless the
device is fully closed and locked. Otherwise partial engagement of
the locking mechanism might lead to failure and possible injury
caused by the high pressure created during an injection
operation.
To ensure that actuation of the application device is not possible
unless the device is fully closed and locked, operation of an
application device according to the invention requires that the
nose part of the application device is pressed uniformly and with a
predetermined force against the skin surface to be injected before
actuation of the application device is enabled. Main objectives of
this security measure are to prevent accidental actuation resulting
in ejection of a liquid jet that might cause eye injury and also to
prevent wasted injections due to premature actuation of the
application device before the nose part thereof is properly pressed
against the skin surface at the injection site.
The outer surface of the application device should riot have any
sharp edges or pinch points and the design of the application
device has to satisfy ergonomic requirements.
The shape of the application device has to be well adapted to the
function it has to perform and therefore the procedures for loading
and unloading a cartridge 11 into the application device and for
actuating the application device should be so obviously and
intuitively clear to the user that a minimum of user instruction is
necessary to ensure proper use of the application device.
Moreover, the application device and in particular the area around
the cartridge nozzle that contacts the skin during the injection
should be adapted to be easily cleaned.
The injection system formed by cartridge 11 and the application
device described hereinafter should be fail-safe and resistant to
tampering. Any faults in the device should result in failure of
device actuation rather than in an unexpected or dangerous
actuation. The design of the latter injection system should be such
that it discourages a "clever" person from modifying or tricking
the device so that it operates improperly.
The application device described hereinafter meets the requirements
outlined above.
As shown by FIG. 2, an application device 41 according to the
invention comprises two sections: a nose section 42 which comprises
a pressure chamber 49 defined by the interior of a shell 43 and
adapted for receiving a cartridge assembly 11, and a base section
44 which comprises among other components a breech block 45 and an
electrical ignition system (not shown in FIG. 2).
Nose section 42 and a base section 44 are assembled in two steps.
In a first step a cartridge 11 is inserted into pressure chamber 49
of nose section 42 and after that nose section 42 and the cartridge
11 inserted thereinto are mechanically connected to base section
44. For this purpose, nose section 42 and base section 44 are
twisted with respect to each other 1/4 turn to provide engagement
of a set of locking lugs.
In a second step nose section 42 is twisted of about one turn with
respect to base section 44 for tightening a screw mechanism that
clamps cartridge assembly 11 with a required preload of e.g. 200
Newton. At this point application device 41 is ready for performing
an injection. For this purpose, the user removes break-off
protective cap 17 from cartridge 11, presses jet orifice 18 of
nozzle body 13 against a skin surface at the injection site, and
then presses an actuation switch to release an injection.
Interlocks prevent actuation of the application device if it is not
fully closed and if the skin contact surface of its nose section 42
is not uniformly pressed against the skin surface.
A spent cartridge is removed by reversing the loading process. For
this purpose, nose section 42 is twisted of about one turn with
respect to base section 44 to release the clamp screw mechanism and
vent the residual cartridge gas pressure. The locking lugs are then
disengaged by a further 1/4 turn, and nose section 42 and base
section 44 are separated from each other so that the spent
cartridge may be removed and discarded.
Application device 41 is a tightly integrated system that comprises
the following subsystems:
Pressure Chamber and Lock
Pressure chamber 49 and a lock which includes the above mentioned
breech block are a set of mechanical components that enclose and
contain a cartridge assembly 11 during a high-pressure
injection.
Housing
A housing encloses and supports the other subsystems which form
part of an application device according to the invention. This
housing also forms the surfaces the user grips to administer
injections and to open and close the application device for
loading, respectively unloading of a cartridge 11.
Electric Ignition System
An electric ignition system includes a battery, an actuation
switch, safety interlock switches and electrical connection leads.
The electrical ignition system supplies electric current to the
ignition contacts 31, 32 of cartridge 11 and thereby to ignition
wire 35 (see FIG. 11) to start an injection process when the user
presses the actuation switch.
Object Sensor
An object sensor comprises a mechanical structure surrounding jet
orifice 18 of nozzle body 13 of cartridge 11. This mechanical
structure comprises a skin contact surface of nose section 42. Two
diametrically opposite places of this skin contact surface must be
pressed against the injection site in order to enable application
device 41 to actuate a cartridge 11 which has been loaded into
application device 41.
The following sections describe each of the above mentioned
subsystems in detail.
Pressure Chamber and Lock Mechanism
FIG. 3 shows a general arrangement of a pressure chamber 49 and a
lock mechanism 51. Pressure chamber 49 is the interior of a
generally cylindrical shell 43 with a reduced diameter opening 46
at one end and a full diameter opening 47 at the other end. The
shell 43 of pressure chamber 49 is manufactured from high strength
steel and dimensioned such that it will withstand about 900 bar
internal pressure (that is three times a 300 bar maximum working
pressure) without damage.
Lock mechanism 51 is part of a mechanical structure contained in
and carried by base section 44. In order to load a new cartridge
into the application device or to unload an spent cartridge from
the application device, nose section 42 and base section 44 are
disassembled as described above in order to separate the shell 43
of pressure chamber 49 from lock mechanism 51.
When cartridge 11 is inserted into pressure chamber 49 break-off
protective cap 17 and the outer end of nozzle body 13 extend
through the reduced diameter opening 46 of the shell 43 of pressure
chamber 49. The shell 43 of pressure chamber 49 has a clearance fit
with respect to cartridge shell 12. During an injection process the
internal pressure within cartridge shell 12 expands it elastically
and its outer wall contacts the internal surface of the shell 43 of
pressure chamber 49, thereby transfers the pressure load to the
shell 43 of pressure chamber 49 during the injection process, and
limits the mechanical stress on cartridge shell 12. After an
injection, the residual pressure in cartridge shell is released by
venting (as described above) and cartridge shell elastically
contracts. This restores the clearance fit of cartridge shell 12
with respect to the shell 43 of pressure chamber 49 and this allows
easy removal of a used cartridge. Nozzle body 13 of cartridge 11
has sufficient strength to bridge the reduced diameter opening 46
and withstand the internal pressure in cartridge 11 during an
injection process.
Full diameter opening 47 of the shell 43 of pressure chamber 49 is
closed when shell 43 is engaged with lock mechanism 51. Lock
mechanism 51 has several functions. A first function of lock
mechanism 51 is that it locks to the shell 43 of pressure chamber
49 and carries the axial pressure force (which is a function of the
cartridge internal diameter and the gas pressure) which tends to
separate lock mechanism 51 from the shell 43 of pressure chamber
49. A second function of lock mechanism 51 is that it carries the
ignition contacts of the application device that engage the
ignition contacts 31, 32 of cartridge 11. A third function of lock
mechanism 51 is that it carries an interchangeable co-volume
setting ring which serves for setting the axial position of the
co-volume seal ring 34 in cartridge 11. A fourth function of lock
mechanism 51 is that it comprises a clamp screw 52 that allows the
user to apply the necessary clamping force on cartridge 11 prior to
actuation thereof, and to release the residual pressure in
cartridge 11 in a slow and controlled way after an injection
process. A fifth function of lock mechanism 51 is that it contains
a mechanical interlock that assures that locking lugs are fully
engaged before clamp screw 52 can be turned to prepare and bring
the system composed by the application device and cartridge 11 to a
state that allows actuation of cartridge 11 by the application
device. Each of these functions is described in more detail in the
following sections.
A pair of male locking lugs 53 on the shell 43 of pressure chamber
49 engage female pockets 54 in a receiver ring 55 of lock mechanism
51 to form a structural connection. The user makes this connection
by inserting locking lugs 53 into receiver ring 55 with an axial
motion, and then rotating the shell 43 of pressure chamber 49 1/4
turn with respect to receiver ring 55 to engage locking lugs 53
with female pockets 54. This type of connection is widely used in
firearms and hose couplings because of its strength and
reliability.
After locking lugs 53 are fully engaged with female pockets 54,
clamp screw 52 is turned to push breechblock 45 into cartridge 11.
Clamp screw 52, the shell 43 of pressure chamber 49, receiver ring
55 and breechblock 45 are all on a common axis, i.e. they are
coaxially arranged. This screw action preloads the sealing of
cartridge 11 with a force of about 200 Newtons, sets the axial
position of co-volume seal ring 34 to a selected position, and
pushes the ignition contacts of the application device against the
ignition contacts of cartridge 11 so that electrical contact is
established between these ignition contacts.
After an injection process is terminated, a 100 bar residual
pressure in cartridge 11 generates a force of about 1600 Newtons on
clamp screw 52. Under this mechanical load, the user turns clamp
screw 52 to retract breechblock 45 and vent cartridge 11. One of
the ends of clamp screw 52 has right hand threads that engage
matching threads in receiver ring 55, whereas the opposite end of
clamp screw 52 has left hand threads that engage matching threads
in breechblock 45. One or more pins in receiver ring 55 engage
matching axial slots in breechblock 45, and prevent rotation of
breechblock 45 while allowing axial motion thereof. The provision
of clamp screw 52 with the above mentioned different threads makes
it possible to obtain an axial displacement of breechblock 45 per
revolution of clamp screw 52 that is twice as long as the axial
displacement that would be obtained if clamp screw 52 had only a
single type of thread with the same thread pitch distance. A
suitable choice of thread diameter and pitch favorably influences
the amount of effort needed for disassembling, respectively
assembling application device 41. This is discussed in more detail
hereinafter.
A pair of interlock levers 56, 57 consisting each of a latch
portion 69 and an arm portion 68 are pivot mounted on a pivot 70 to
the receiver ring 55. Interlock levers 56, 57 lie in a plane that
includes the symmetry axis of receiver ring 55, and the pivot axes
are perpendicular to this plane and symmetrically placed on each
side of the symmetry axis of the receiver ring. Interlock levers
56, 57 are spring biased by a bias spring 60 so that the latch
portions 69 engage a pair of grooves (not shown) in clamp screw 52,
preventing screw rotation. When the shell 43 of pressure chamber 49
is inserted into receiver ring 55, the arm portions 68 of interlock
levers 56, 57 slip into a pair of cam grooves 58, 59 in the shell
43 of pressure chamber 49. Cam grooves 58, 59 are shaped to move
the arm portions 68 of interlock levers 56, 57 as the shell 43 of
pressure chamber 49 is rotated to engage locking lugs 53, so that
the latch portions 69 are removed from the clamp screw grooves. The
result is that rotation of clamp screw 52 is only possible when the
locking lugs 53 are fully engaged with pockets 54.
A second function of interlock levers 56, 57 is to prevent rotation
of lugs 53 and disengagement thereof from pockets 54 once clamp
screw 52 is rotated from the starting position to clamp cartridge
11 and thereby the closure plug of cartridge 11 and pressure
chamber 49 by means of breechblock 45. When clamp screw 52 is
rotated, the latch portions 69 of the interlock levers 56, 57 ride
on the outside diameter of clamp screw 52, and can no longer enter
the clamp screw grooves and rotate about pivots 70. The arm
portions 68 of interlock levers 56, 57 are therefore immovable, and
bear against the sides of the cam grooves 58, 59 in the shell 43 of
pressure chamber 49 and block rotation of locking lugs 53. This
ensures that lugs 53 remain fully engaged with pockets 54 during
actuation of cartridge 11 and can only be disengaged after clamp
screw 52 is returned to the starting position. At this point the
latch portions 69 of interlock levers 56, 57 can again drop into
the clamp screw grooves, allowing the latches 69 of interlock
levers 56, 57 to rotate about the pivots 70.
A third function of interlock levers 56, 57 is to prevent shell 43
of pressure chamber 49 from being inserted if clamp screw 52 is not
in the starting position. In this condition the latch portions 69
of the interlock levers 56, 57 ride on the outside diameter of
clamp screw 52, displacing the arm portions 68 of the levers so
that they do not enter the cam grooves in the shell 43 of pressure
chamber 49. This blocks the shell 43 of pressure chamber 49 from
entering the receiver ring 55 far enough for the locking lugs 53 to
engage pockets 54. The situation in which the shell 43 of pressure
chamber 49 is removed and the clamp screw 52 is not in the starting
condition is not normal, and indicates damage or tampering.
Correction of this anomalous state requires device service or
replacement.
By careful selection of the design parameters of clamp screw 52,
the required effort to assembly and disassembly application device
41 are approximately equal and this results in greatly improved
ease of use.
Frictional torque of clamp screw 52 varies in function of axial
load, screw thread diameter, and friction coefficient. Load
reaction torque varies in function of axial load and thread pitch.
The reaction torque adds to the friction torque in the closing
direction (when assembling application device 41), and increases
the user effort. Conversely, the reaction torque subtracts from the
friction torque in the opening direction (when disassembling
application device 41) and assists the user. Since the axial force
is about 200 Newtons in the closing direction and about 1600
Newtons in the opening direction, according to the invention the
parameters of clamp screw 52 are selected to equalize the opening
and closing torque. The following table summarizes the results of a
typical design calculation.
TABLE-US-00001 Parameter Value Clamp screw diameter 8 mm Screw
thread friction coefficient 0.12 Peak closing force 200 N Peak
opening force 1600 N Equalized opening and closing torque 20 N-cm
Screw pitch (Total of left and right 6 mm hand clamp screw
sections)
Housing
FIG. 4 shows a cross section of application device 41 including the
housing components. As well as containing the functional
components, the housing has important functions of its own. The
nose section 42 of the housing is rigidly connected to the shell 43
of pressure chamber 49, and serves as one handle through which the
user applies opening and closing torque. The base section 44 of the
housing is rigidly connected to clamp screw 52, and serves as the
other handle. The base section 44 of the housing rotates relative
to the receiver ring 55 and breechblock 45. In combination, the
nose section 42 and the base section 44 of the housing also act as
visual and tactile indicators, since they have oval profiles that
line up when the device is fully closed. Closure of application
device 41 is assisted by a spring-loaded pin and detent 61 that
latch the application device 41 in the closed position. Additional
functions and features of the housing will become evident in the
descriptions of other aspects of application device 41.
FIGS. 5 to 9 show various views of the nose section 42 and of some
of its components. FIG. 5 shows a side view of the nose section 42
of an application device of the kind shown by FIG. 4. FIG. 6 shows
a first perspective view of the nose section 42 shown by FIG. 5.
FIG. 7 shows a second perspective view of the nose section 42 shown
by FIG. 5. FIG. 8 shows a first exploded view of components of the
nose section 42 shown by FIGS. 5-7. FIG. 9 shows a second exploded
view of components of the nose section 42 shown by FIGS. 5-7.
Electric Ignition System
FIGS. 10 and 11 show schematic representations of the electric
ignition system of application device 41.
In its simplest form, the electric ignition system of application
device 41 consists of a battery 62, an actuation switch 63
controlled by the user, electrical contacts that engage electrical
contacts of cartridge 11, and interconnection conductors. The user
loads a fresh cartridge 11 into application device 41, closes and
locks this device, removes break-off protective cap 17, presses jet
orifice 18 against the skin at the injection site, and then presses
push button 63 of the actuation switch. Current passing through an
electrically heated wire in the gas generator of cartridge 11
lights the propellant and starts the injection. The invention uses
this basic approach, and adds interlock mechanisms to reduce the
chance of premature actuation that could cause a hazard or waste an
injection cartridge.
The physical configuration of the electric ignition system of this
invention is illustrated in FIG. 4. Except as noted, the ignition
components are attached to the base section 44 of the housing.
Battery 62 is permanently connected by soldering or a similar
means, and will normally last the life of application device 41.
The positive battery terminal 64 is electrically connected to the
input terminal of the normally open actuation microswitch 71, and
the negative terminal 65 is connected to the input terminal of the
normally open interlock microswitch 72. The output terminal of the
actuation microswitch 71 is connected to a conductive spring member
73 that is biased into contact with the central ignition contact
pin 66. This contact connection is required since the central
ignition contact pin 66 rotates with the receiver ring 55, not with
the base section 44 of the housing. The output terminal of the
interlock microswitch 72 is connected to a conductive spring member
67 that is biased into contact with the sliding conductive transfer
pin 74 in the receiver ring 55. The transfer pin 74 forms a
conductive path from the conductive spring member 67 to the
co-volume setting ring 48 and then to the breechblock 45. Because
the base section 44 of the housing and the receiver ring 55 have
rotational and axial relative motion, contact takes place and
ignition is possible only when clamp screw 52 is in the
predetermined actuation position.
The central ignition contact pin 66 presses against the cartridge
center ignition contact 32. The pin head 75 is structurally
connected to the sliding breechblock 45, but electrically isolated
by an insulating bushing 76. The pin shaft passes through clearance
holes in the breechblock 45 and clamp screw 52, and is supported on
center by an insulating sleeve bearing 77 to maintain electrical
isolation.
The electrically conductive sliding breechblock 45 presses against
the outer ignition contact 31 of cartridge 11. As described above,
current can only flow to the breechblock 45 when the clamp screw 52
is in the actuation position and the transfer pin 74 makes contact
with the conductive spring member 67.
When the interlock microswitch 72 is closed and the clamp screw 52
is in the actuation position, the actuation microswitch 71 is the
only remaining barrier to current flow through the ignition
contacts and the electrically heated wire 35 in cartridge 11. This
results in the battery voltage appearing between the input and
outlet terminals of the actuation microswitch 71. This "ready to
actuate" condition is visually indicated by a LED 78 connected
across the terminals. Actuation then takes place when the user
closes the actuation microswitch 71 by pressing push button 63.
A mechanism consisting of a pushbutton 63, coil spring 81, pin
lever 82 and flat spring 83 is used to close the actuation
microswitch 71 when the user presses the push button 63. This
arrangement allows the pushbutton 63 to be positioned so that it is
convenient for the user, while the actuation microswitch 71 is
positioned where housing space is available. The pushbutton 63
slides in a sleeve 84 in the housing, and is biased out by the coil
spring 81. The pin lever 82 serves a dual purpose. First, it is
pressed into the pushbutton 63 and extends into openings in the
sides of the sleeve 84 to retain the pushbutton 63 in the housing.
Second, it acts as a lever that transfers the pushbutton motion to
the flat spring 83 that engages the actuation microswitch operating
plunger 85. The pin lever 82 pivots in a hole in the side of the
sleeve 84 nearest the nose section 42 of the housing of the
application device 41, and swings through a slot 86 in the opposite
side. The flat spring 83 is anchored at one end, and passes over
the microswitch 71 and extends to engage the end of the pin lever
82. When the pin lever 82 swings, it deflects the flat spring 83
towards the actuation microswitch 71 and pushes the actuation
plunger 85. The sleeve 84 in the housing is made of translucent
plastic that is illuminated by the "ready to actuate" LED 78.
The schematic representation of the electrical ignition system
shown by FIG. 10 illustrates the fact that in order that an
injection can be performed with application device 41 the following
switches have to be closed: switches 71, 72, and switch formed by
lock mechanism 51, spring-loaded pin and detent 61 and electrical
conductive transfer pin 74. This latter switch is only then closed
when the application device 41 is completely assembled, that is
when the components contained in nose section 42, in base section
44, and the cartridge 11 are all in the proper position with
respect to each other.
The schematic representation of the electrical ignition system
shown by FIG. 11 illustrates the state of this system when the
application device 41 is completely assembled and all necessary
contacts for the ignition are established with exception of
switches 71 and 72 which are still open. In this state LED 78
received a current limited by resistor 79. This current is well
below the value necessary to cause ignition by electrically heating
ignition wire 35, but is large enough to cause light emission by
LED 78 and thereby signalize that application device 41 would
become ready for performing an injection if and when properly
positioned on the injection site.
When the application device 41 reaches a proper position on the
injection site, switch 72 is closed by this positioning, and
actuation of push button 63 by the user can then cause closure of
switch 71. If this happens, the electrical ignition circuit is
closed and a sufficiently large current is fed to ignition wire 35
to cause ignition of the propellant in cartridge 11.
Object Sensor/Position Detector
The object sensor or position detector requires the nose section 42
of the housing of the application device 41 to be pressed uniformly
against the skin surface at the injection site before actuation is
possible/allowed. The object sensor/position detector is
illustrated in FIG. 4. The nose section 42 of the housing includes
a flat annular surface 91 which surrounds the end of the shell 43
of pressure chamber 49 that protrudes from the housing and the
injection nozzle. A pair of diametrically opposed sensor pins 92,
93 slide in holes in the housing, and their ends extend a short
distance above the surface in the rest position. The interlock
system according to the invention requires that both sensor pins
92, 93 are pushed flush with the annular surface 91 to enable
execution of an injection. Sensor pins 92, 93 support a concentric
rigid metal sensor ring 94 that is free to pivot at the contact
points with the sensor pins 92, 93. This defines the condition that
two or more separate points must be pressed to push the sensor ring
94 and both pins 92, 93 flush with the annular surface 91 and
enable execution of an injection. If the sensor ring 94 is pressed
at any one point around its circumference it will tip, and at most
one of the two sensor pins 92, 93 will be pushed flush with the
annular surface 91. The annular area, including the sensor ring 94
and sensor pins 92, 93, is covered by a flexible rubber boot 95.
The inner edge of the boot 95 is bonded to the shell 43 of the
pressure chamber 49 at a bond point 105, and the outer edge of boot
95 fits in a groove in the nose section 42 of the housing. The boot
95 forms a smooth, easily cleaned surface and protects the
mechanism. It also retains the sensor ring 94 and holds it in the
proper spatial relationship with the sensor pins 92, 93 at the rest
position.
The sensor pins 92, 93 push a relay ring 96 inside the nose section
42 of the housing. The relay ring 96 in turn pushes a tilt plate
97. The tilt plate 97 contacts the relay ring 96 with two
diametrically opposed raised pivot points 98 (98a respectively
98b), and two diametrically opposed legs 99 (99a respectively 99b)
extend towards the base section 44 of the housing. The legs 99 are
offset 90 degrees from the pivot points 98, and lie in the same
plane as the sensor pins 92, 93. A return spring 101 formed from
sheet spring material pushes the tilt plate 97, relay ring 96 and
sensor pins 92, 93 towards the nose section 42 of the housing so
that the sensor ring 94 is pushed out to the rest position. A cover
plate 102 on the surface of the nose section 42 of the housing that
abuts the base section 44 of the housing supports the return spring
101 and shields the mechanism. The tilt plate legs 99 pass through
holes in the cover plate 102, with their ends flush with the outer
surface in the rest position.
When the nose section 42 of the housing is attached to the base
section 44 of the housing and the clamp screw 52 is locked, one of
the two tilt plate legs 99 is aligned with the interlock push pin
103. This pin contacts the interlock microswitch plunger 104, and
closes the interlock microswitch 72 when it is pushed by one of the
tilt plate legs 99. The other tilt plate leg contacts the base
section 44 of the housing and forms a pivot point. If the sensor
ring 94 pushes both sensor pins fully, then the relay ring 96 is
pushed uniformly against the two tilt plate pivot points. This
causes the tilt plate 97 to rotate around the pivot point formed by
the leg in contact with the housing so that the other leg extends,
pushes the interlock push pin 103, and closes the interlock
microswitch 72. In the event that only one sensor pin 92 or 93 is
pushed, the relay ring 96 tilts rather than moving uniformly. The
two points on the relay ring 96 that contact the tilt plate 97
pivots move only half the full distance, with the result that the
tilt plate leg 99 moves only half the full distance and does not
close the interlock switch 72.
This above described object sensor/position detector has a number
of useful features. First, it is electromechanical, and does not
contain any electronic devices that are sensitive to and whose
operation can be affected by spurious signals from electrostatic
discharge or other sources of electromagnetic interference. Second,
the electric ignition circuit is totally within the base section 44
of the housing, with no connections to the removable nose section
42 of the housing that could compromise reliability. Third,
additional safety is provided by the fact that the device must be
fully closed and locked to align the tilt plate leg 99 with the
interlock push pin 103. Fourth, the structure of the object
sensor/position detector is symmetrical, so that the nose section
42 of the housing may be connected to the base section 44 of the
housing in either of two positions which are angularly spaced from
each other of 180 degrees.
TABLE-US-00002 List of reference numbers 11 medication
cartridge/cartridge assembly 12 cartridge shell 13 nozzle body 14
flexible container wall 15 medication reservoir 16 liquid
medication 17 break-off protective cap 18 jet orifice 19 20 21
envelope 22 fluid channel 23 gas generator body 24 propellant
chamber 25 outlet orifice plate 26 closure plug/closure plate 27
gas pressure chamber 28 annular co-volume 29 30 31 ignition contact
32 ignition contact 33 internal support 34 co-volume seal ring 35
electrically heated wire/ignition wire 36 37 38 39 40 41
application device 42 nose section 43 shell of pressure chamber 44
base section 45 breech block 46 reduced diameter opening 47 full
diameter opening 48 co-volume setting ring 40 pressure chamber 50
51 lock mechanism 52 clamp screw 53 male locking lugs 54 female
pockets 55 receiver ring 56 interlock lever 57 interlock lever 58
cam groove 59 cam groove 60 bias spring 61 spring-loaded pin and
detent 62 battery 63 push button/actuation button 64 positive
terminal 65 negative terminal 66 central ignition contact pin 67
conductive spring member 68 arm portion 69 latch portion 70 pivot
71 actuation micro-switch 72 interlock micro-switch 73 electrical
conductive spring member 74 electrical conductive transfer pin 75
pin head 76 insulating bushing 77 insulating sleeve bearing 78
Light Emitting Diode (LED) 79 electrical resistance 80 81 coil
spring 82 pin lever 83 flat spring 84 sleeve 85 operating
plunger/actuation plunger 86 slot 87 88 89 90 91 flat annular
surface 92 sensor pin 93 sensor pin 94 metal sensor ring 95
flexible rubber boot 96 relay ring 97 tilt plate 98 pivot point
(98a, 98b) 99 leg (99a, 99b) 100 101 return spring 102 cover plate
103 interlock push pin 104 interlock microswitch plunger 105 bond
point
Although a preferred embodiment of the invention has been described
using specific terms, such description is for illustrative purposes
only, and it is to be understood that changes and variations may be
made without departing from the spirit or scope of the following
claims.
* * * * *